Low-Cost, Compact Protein Biomarker Sensors Based on Lens-Free Microscopy

Oct 27, 2021
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About This Webinar
Many biomedical diagnostics require quantifying levels of specific protein molecules in blood, saliva, or other bodily fluids. Antigen tests for COVID-19 are a recent example. Lens-free holographic microscopy has been applied to many bioimaging tasks because it is compact and inexpensive, and it can image an ultralarge field of view with submicron resolution. However, it has not previously been applied to protein sensing in solution. Euan McLeod demonstrates the application of lens-free holographic microscopy to the sensing of specific proteins in aqueous solution, in an approach his group calls quantitative large-area binding (QLAB).

In QLAB, beads coated with receptors for the target protein are imaged, and the bead clustering that results when the target protein is present is quantified using automated image processing. McLeod and his team use biotin-coated beads to sense dissolved NeutrAvidin, and antibody-coated beads to sense dissolved interferon gamma, which is a cytokine molecule that is a biomarker for inflammatory and infectious diseases. Limits of detection are in the nanograms per milliliter (ng/mL), or hundreds of picomolar (pM), range. The group believes QLAB sensors will be useful for rapid and low-cost field-portable or point-of-care diagnostics.

***This presentation premiered during the 2021 BioPhotonics Conference. For more information on Photonics Media conferences, visit 

About the presenter:
Euan McLeodEuan McLeod, Ph.D., is an associate professor in the Wyant College of Optical Sciences at the University of Arizona (UA). He joined UA's faculty in 2015. He is also an associate professor at the UA BIO5 Institute and an affiliate member of the UA Cancer Center. McLeod is a senior member of the Optical Society of America, and he won an NSF CAREER award in 2021. He was previously a postdoc in electrical engineering and bioengineering at UCLA, as well as a postdoc in applied physics at Caltech. He received his doctorate from Princeton University and his Bachelor of Science from Caltech. McLeod's background and interests lie at the intersection of optics, nanoscience, and soft biomaterials science. He has published more than 35 papers on these topics in peer-reviewed journals, with major contributions in the areas of high-speed varifocal lenses based on acoustic modulation; lens-free holographic imaging of nanoparticles, viruses, and biomarkers; and the use of optical tweezers in fabricating micro- and nanostructured materials.
MicroscopyBiophotonicscoronavirusholographic microscopyCOVID-19lens-free holographic imagingspectroscopy
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